Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices), as well as fingerprint sensors, are widely used in a variety of electronic systems. Proximity sensor devices typically include a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Fingerprint sensors also typically include a sensing region in which the fingerprint sensor determines presence, location, motion, and/or features of a fingerprint or partial fingerprint.
Proximity sensor devices and fingerprint sensors may be used to provide interfaces for the electronic system. For example, proximity sensor devices and fingerprint sensors are often used as input devices for larger computing systems (such as opaque touchpads and fingerprint readers integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices and fingerprint sensors are also often used in smaller computing systems (such as touch screens integrated in cellular phones). Such devices and sensors are often susceptible to a variety of types of noise. In certain instances, signal quality is significantly degraded if such noise is not rejected by the system.